D meson production in e+e- annihilation

The production of D mesons in e+e- annihilation for the center-of-mass energy range 3.7 to 7.0 GeV has been studied with the MARK I magnetic detector at the Stanford Positron Electron Accelerating Rings facility. We observed a resonance in the total cross-section for hadron production in e+e- annihilation at an energy just above the threshold for charm production. This resonance, which we name psi'', has a mass of 3772 +- 6 MeV/c2, a total width of 28 +- 5 MeV/c2, a partial width to electron pairs of 345 +- 85 eV/c2, and decays almost exclusively into D anti D pairs. The psi'' provides a rich source of background-free and kinematically well-defined D mesons for study. From the study of D mesons produced in the decay of the psi'' we have determined the masses of the D0 and D+ mesons to be 1863.3 +- 0.9 MeV/c2 and 1868.3 +- 0.9 MeV/c2 respectively. We also determined the branching fractions for D0 decay to K-π+, anti K0π+π- and K-π+π-π+ to be (2.2 +- 0.6)%, (4.0 +- 1.3)%, and (3.2 +- 1.1)% and the branching fractions for D+ decay to anti K0π+ and K-π+π+ to be (1.5 +- 0.6)% and (3.9 +- 1.0)%. The average number of kaons per D decay was found to be 0.52 +- 0.14 K0,s and 0.42 +- 0.12 K+,s. The rate for inclusive production of D mesons at center-of-mass energies above the psi'' has been measured; we find that it can account for most, if not all, of the observed increase in the total hadronic cross-section for center-of-mass energies above 4 GeV. The inclusive momentum and energy spectra for D's have been measured at the highest available center-of-mass energy (7 GeV). The energy spectra are rapidly decreasing functions of energy with a slope similar to the slope of the charged pion spectrum at the same center-of-mass energy. This behavior suggests that the fragmentation function of the charmed quark into charmed mesons is a decreasing function of the scaling variable z = 2E/sub D//E/sub CM/